Machine components made of cast iron with rubbing surfaces on which sealing elements slide are in wide use in technology as cast iron is a cheap material which exhibits low wear when used in conjunction with suitable co-operating materials. The low wear is attributable to the free graphite contained in the iron, which graphite acts as a lubricant for the rubbing surface. For example on this basis the internal surfaces of cylinders, against which piston rings or other sealing elements slide, are often made of such cast irons. In machines having cylinders with such cast iron surfaces, in particular internal combustion engines, a certain running-in period is generally prescribed in order to avoid "seizing", i.e. local welding of the sealing elements to the rubbing surfaces. The running-in process has been looked upon as a smoothing or polishing process by which the high points or roughnesses produced in manufacture of the rubbing surfaces are smoothed off. In order to be able to shorten or completely eliminate the running-in period it is known to harden such rubbing surfaces, for example inductively, but this brings with it certain drawbacks, amongst others the danger of cracking and distortion. Moreover it means that one has to employ particular kinds of cast iron which are capable of being hardened. Finally it causes an increase in the wear of the sealing elements that run against the surface in question.